MD1000 Redundancy

Question

Is it possible to have a single MD1000 connected to 2 PERC5 cards in a single server to have redundant controllers?     If not, what would the results be if the lone PERC5 card went bad and had to be replaced?  Would the replacement card see the existing array on the MD1000?

Storagetalk · Answer

Well, in order to have a lone MD1000 connected to two controlers you'd have to be in split mode.  You can't connect both EMM's on the MD to two connectors and be in unified mode.  You'll get an 'unsupported cabling' message at boot on the managament server.   The PERC 5's themselves have no internal memory...all the config data is stored on the hard drives on the MD.  So it would see things just fine.

Dev Mgr · Answer

If you're looking into a solution with redundant controller, you'll have to look into buying a SAN solution. Dell offers the AX150, CX300 and CX3-20/40/80 systems for setups with redundant controllers and multiple paths to your storage.

munyoki · Answer

i'd like clarification on this also. we brought an extra controller incase the main one went done, but i wasnt planning on actually hooking up the MD1000 to BOTH controllers at the same time. can some1 please confirm that both controllers will see the array(s) and there will be no issues even if the main(?) card dies? thanx in advance.

Times Prince · Answer

Contoller redundancy is provided in a SAS solution by the MD3000 storage subsystem.   This solution is similar to your MD1000 except it has the RAID controllers in the SBB compatible slots instead of EMMs.   The two RAID controllers communicate with each other via backplane SAS links and will share memory, and have fully automatic failover capability.    Each RAID controller communicates to the server using a SAS 5E HBA, and host software provided with the solution provides failover at this level as well.   If you really want controller redundancy in a low cost SAS solution the MD3000 is the way to go.

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